section 1: vessel handling - coxswain training information · manoeuvres to shorten in cable and...

Section 1: Vessel Handling

Section 1:

Vessel

Handling

Learner's Guide -ABF 521: Nautical Knowledge Coxswain


Section Contents Page

Section 1: Vessel Handling 9

Learning Outcome 1 13

Assessment Criteria 13

Conditions 15

Section Introduction 15

Section learning sequence 16

1.1 Manoeuvring Characteristics 16

1.2 Effects of External Forces on

Vessel Handling 22

1.3 Anchoring 31

1.4 Berthing/Unberthing a Vessel 36

1.5 Securing a Buoy 39

1.6 Towing 41

Section Summary 43

Check your progress 44

Learner's Guide - ABF 521: Nautical Knowledge Coxswain 11


Section learning outcome

Learning outcome 1

On completion of this learning outcome the learner will be able to manoeuvre

a power driven vessel of less than 12 metres in length in various conditions of

tide and weather to carry out operations of small commercial vessels in

sheltered and inshore waters.

Assessment Criteria:

• Explain the differing manoeuvring characteristics of a small power

driven vessel with regard to:

effects of displacement and planning hulls

outboard and inboard engines

stopping distance

response to rudder movements at varying speeds

transverse thrust of propeller

single propeller and twin propeller propulsion units

• List precautions to be taken and explain actions to counter the

effects of external conditions on manoeuvring a vessel including:

tidal streams

confined waters

poor visibility

heavy weather conditions including strong winds, high sea

state, heavy swells and surf

proximity to other vessels that are berthed, at anchor,

underway but stopped, or underway and making way

particularly large vessels

crossing a river entrance bar



• Manoeuvre a vessel to let go and weigh anchor demonstrating:

briefing requirements for crew

preparations for letting go

manoeuvring to let go and lay out cable

an ability to assess when a vessel "has its cable" or the

anchor is holding

an ability to recognise when an anchor is dragging

manoeuvres to shorten in cable and weigh anchor

procedures for securing the anchor for sea

a knowledge of the different types of anchors and their se

a knowledge of the factors to be considered in choosing an

anchorage

• Manoeuvre a vessel to berth and cast off from alongside a wharf

demonstrating:


safety requirements onboard

correct manoeuvring actions for the prevailing conditions of

wind and tide

• Manoeuvre a vessel to come to and slip from a buoy or pick up a

mooring demonstrating:


safety requirements onboard

correct manoeuvring actions for the prevailing conditions of

wind and tide

• Manoeuvre a vessel to take another small vessel in tow

demonstrating:

briefing requirements for own crew and master of the other

vessel

safety requirements and preparations towing vessel and vessel

being towed

correct manoeuvring actions for the prevailing conditions and

types of vessels to approach the other vessel, pass and take up

the tow and subsequently release the tow

14 Learner's Guide -ABF 521: Nautical Knowledge Coxswain


Conditions:

Assessment will include written and/or oral tests and practical assessment

tasks

in the workplace

on board a vessel of appropriate size and power in survey

in a simulated environment

on a training vessel

You could be asked to demonstrate your knowledge and practical skills in:

Manoeuvring a vessel to berth, unberth or anchor.

Manoeuvring a vessel to pick up a person overboard

Manoeuvring a vessel to moor at a buoy

Towing a vessel

Section introduction

In this section we will examine the factors that affect the manoeuvring

characteristics of a vessel and the difference between the manoeuvring

characteristics of various types of vessels with differing propulsion. You

will then further examine how to manoeuvre a vessel to berth, unberth, moor,

and anchor a vessel.

Learner's Guide -ABF 521: Nautical Knowledge Coxswain 15


Section learning sequence

• Manoeuvring Characteristics.

• Effects of External Forces on Vessel Handlling

• Handling

• Anchoring

• Berthing/Unberthing

• Securing a Buoy

• Towing

1,.1 Manoeuvring Characteristics

To carry out safe and satisfactory manoeuvres at close quarters requires a

knowledge of the handling qualities built into a craft and a sound understanding

of the basic techniques for making the best use of these qualities.

Many design features will affect the handling of any craft, the most important are:

The underwater profile

The windage effect of hull and superstructure

The rudder or steering device

The size and efficiency of the propeller or propulsion device

The underwater profile

Three profiles are shown in the above sketches.

The craft on the left, a displacement motor vessel, has a long straight keel

and a large wetted surface. Such a craft will hold its course well, will

respond slowly to the helm and be little effected by windage.

The craft in the middle, a yacht, has a deep yet short keel concentrating the

wetted area midships. Such a craft will be easy to deviate from her course and

respond readily to the helm. It will also be little effected by windage.

16 Learner's Guide - ABF 521: Nautical Knowledge Coxswain


The third vessel is of light displacement, flat bottomed with little wetted

surface area. It will not respond well to the helm and be adversely effected

by windage.

The longitudinal point around which a vessel turns is known as its' pivot

point. The pivot point of a vessel is largely determined by its' underwater

shape. For most small vessels with inboard engines it is about 0.33 of the

length of the vessel from the bow.

The rudder

A rudder operates by deflecting the water flowing over its surface. Its

effectiveness is governed by the surface area (size), the speed of the water

passing over it and the angle of deflection.

The angle of deflection is controlled by the helm setting to a maximum of 35

to 40 degrees.

water flow past a rudder ahead,

Vessels that travel at low speeds will require a large rudder to handle well.

Those that travel at high speed generally have small rudders and will

respond well to the helm at speed, at low speed the rudders will have little

effect and response to the helm will diminish.



The rudder is generally placed directly astern of the propeller. When

forward power is engaged the propeller 'pumps• water over the rudder

surface increasing its efficiency and steerage. When power astern is engaged

the propeller 'sucks' water from astern with minimal flow past the rudder as

the propeller thrust goes towards the bow. This is why the rudder is more

effective when propelling ahead than astern. If astern propulsion is applied

while the vessel is moving forward, water movement around the rudder will

be confused and the rudder will probably have no effect at all.

The propeller

The correct term for the propeller is the screw propeller. As the propeller

turns it screws its way through the water and draws the boat along. The

power created by this action is called axial thrust.

You will commonly hear the size of propellers referred to as two figures, eg

300 x 250. The first figure refers to the overall diameter (300 mm in this

case), the second to the pitch (250 mm). The term 'pitch' describes how far

that propeller would draw the vessel forward (or astern) in one revolution

were it 100% efficient.

Propellers can be made for engine and gearbox combinations that turn the

shaft in either direction. They are described as either right or left handed.

Looking from astern a right banded propeller turns in a clockwise direction

for forward power and anti-clockwise for astern. For a left banded propeller

the opposite applies.

The propeller rotates and draws us along using axial thrust and produces a

side effect called transverse thrust, also known as paddle wheel effect or

prop walk. Transverse thrust is caused by the increase in water pressure and

density with depth making the propeller blades more efficient at the bottom

of their rotation. The water flow to the blades at the top of the rotation may

also be adversely effected by hull form and obstructions.


...... ----

1

--


Transverse thrust has the effect of trying to tum the vessel. A right handed

propeller will 'walk' the stern of a vessel to starboard and the bow will

swing to port when forward power is applied. A helmsperson automatically

corrects for this by applying a small helm adjustment. In the same vessel

when power astern is engaged the stem will 'walk ' to port and the bow

swings to starboard. Adjustments to the helm will not counteract this.

Remember: The direction of 'walk' and bow swing will be the opposite for

a left handed propeller. Transverse thrust is most noticeable when power is

first applied. It is more noticeable when going astern than ahead.

BOW SWINGSTOPORT

STERN SWINGS TO STARBOARD WHEN GOING

AHEAD

STERN SWINGS TO STARBOARD WHEN GOING ASTERN

-

The effect of transverse thrust with a right handed propeller going ahead and astern is the opposite of a left handed propeller.

The propeller/gearbox combined with the available power will decide how the

vessel will respond to the throttle. High speed vessels with a small diameter

heavily pitched fast spinning propeller and vessels designed for towing with a

large diameter moderately pitched slow spinning propeller will normally

respond well to the throttle. Vessels designed to steam economically will

normally react poorly to the throttle getting underway and stopping slowly.

Learner's Guide -ABF 521.: Nautical Knowledge Coxswain 19


Outboard engines steer well ahead and astern when in gear with no effecti ve

steering in neutral. Twin outboards have some similar characteristics to

twin screws.

• Written Activity 1 Describe the manoeuvring characteristics of your vessel.

Twin Screw Vessels

In twin engined vessels the propellers are normally counter rotating. That is,

the starboard hand propeller is normally right handed and the port propeller

left banded.

There are numerous benefits of having twin propellers, those that effect vessel

handling are listed below:

Extremely manoeuvrable

Steering without a rudder

Negating transverse thrust


)


Manoeuvreability

Due to the configuration of the propellers it possible to tum a twin screw

vessel around more easily than one with a single screw. To carry out this

manoeuvre engage ahead on one engine and astern on the other. Then adjust

the throttles, a few more revs are generally required on the astern engine to

prevent forward progression. This action would cause the vessel to tum on

the spot.

Steering without a rudder

Whether going ahead or astern a twin screw vessel may be steered by adjusting

the revolutions and/or gear of each propeller.

Negation of transverse thrust

When both engines are engaged either ahead or astern each negates the

transverse effect of the other and the vessel should track straight. Transverse

thrust still exists and can be used to advantage in vessel manoeuvring.

You can estimate how you would expect a vessel to perform from a visual

inspection, only with practice and experience will you get a feel for that

particular vessels manoeuvring characteristics. For this reason it is essential to

observe someone else while they are manoeuvring the vessel and also practice

under the supervision of a person who is familiar with the handling

characteristics of that vessel.

_earner's Guide - ABF 521: Nautical Knowledge Coxswain 21

Section 1: Vessel Handl ng

1.2 Effects of External Forces on Vessel Handling

1.2.1 Wind

The hull and superstructure of an vessels act as a sail. The effect is most

noticeable when beam on to the wind and a light displacement vessel with

little wetted area is going to be effected more than a displacement vessel

with large wetted area.

This area exposed to the wind is known as the "windage area" and a large

superstructure either forward or aft will affect handing by creating excessive

windage’ in that area.

The angle between the ships' head and its course through the water,

attributed to the wind, is known as "leeway". Leeway is commonly observed

by noting the difference between the vessels' wake and the course steered.

The effect of the wind varies according to the windage area of the vessel and

it is important for you as the Master to be familiar with the effect of the

wind on your vessel in various conditions of loading.

•Written Activity 2

Identify your vessel's. windage area. Describe the effect windage has on manoeuvring your vessel whilst berthing and turning abreast.



Current

Tidal streams and currents move a body of water in a particular direction. In a

close manoeuvring situation, such as berthing or picking up a buoy, by

approaching into (stemming) the tidal stream or current the vessel will have

greater manoeuvreability at slow approach speeds (due the flow of water past

the rudder) and a shorter stopping distance.

If the current or tidal stream is in the same direction as the approach, the vessel

will have poor steerage at slow approach speeds and increased stopping distances,

with a resultant increase in transverse thrust. However, if the current is from

abeam it would again cause problems preventing the vessel from coming

alongside the berth or bringing the vessel alongside at an increased speed.

The wind and current will always have an effect on your vessel and will need to be taken into consideration in all aspects of a voyage. Learn., where

possible, to use them to your advantage especially when berthing,

unberthing, anchoring, picking up or leaving a buoy.

1.2.2 Confined Waters

The motion of a ship causes an increase in water pressure at the bow and

stern and a reduction in pressure amidships. Interaction occurs when the

normal flow of water around the bull is restricted by the influence of a nearby

external source such as a breakwater, dredged channel, shallow water or by

the close passage of another vessel (interaction between vessels is dealt

with in section 1.2.5).

In shallow water, vessels may experience significant changes in

manoeuvring characteristics including loss of rudder effect, changes in

transverse thrust or, most noticeably a reduction in vessel speed

accompanied by a change in trim. The change in trim to a vessel may be by

the head or by the stern depending on the hull form of the vessel. This

change of trim is commonly known as 'Squat' (Shallow Water Effect, or

Smelling the bottom) and has the effect of increasing draft when this is least

desirable. Vessels with fine hull lines will squat by the stem and a barge

shaped vessel will tend to squat by the head.


·e·

\ SLCTION

-·· -- -- - -· ---------


Squat can be reduced by the reduction of speed, as this reduces the speed of

the water passing below the hull, reducing the intensity of the low pressure

area under the vessel and therefore the vessel does not "sink" as much into the

low pressure area.

When operating in proximity of breakwaters, dredged channels or steep banks

allowances need to be made for the effects of Interaction. The bow and stern

of the vessel will be repelled whilst the body of the vessel will be attracted to

the obstruction. This creates little problem if the obstruction is continuous and

you can travel in the middle of the channel created, all the forces balance. If it

is not continuous or you must travel on one side you will need to compensate

for these effects.

1.2.3 Poor Visibility

EFFEC T

When operating in or near an area of restricted visibility you must navigate

with extreme caution, taking into account the factors considered in the

International Collision Regulations and best practice of seamanship.



1.2.4 Heavy Weather Handling

Ideally a vessel at sea should avoid heavy weather conditions, this is often

not possible. If adverse weather is expected or encountered action should be

taken to ensure the safety of the vessel, passengers and crew.

A prudent ship's Master should be aware of the vessel's sea handling ability,

knowledge of the vessel's stability, how to handle the vessel in adverse

weather conditions and steps to take to prepare the vessel for heavy weather.

Check:

• The anchor gear to see that the anchor is secured, the stopper fitted, winch

brake on, spurling pipe and any other openings made watertight.

• Heavy objects or cargo that could be safely stowed below decks should be

shifted.

• Deck cleared of any loose debris or equipment. All equipment on deck is

made secure.

• All watertight doors, hatch covers and openings to below deck secured

and water tight.

• Freeing ports and scuppers checked to see they are free and working and a

deck life line rigged.

• Bilges should be pumped, and any tanks, if possible, either emptied or

pressed up to reduce loss of stability through "free surface" effect.

• Engine, steering gear. Perform routine checks and maintenance.

• Lifesaving and firefighting appliances ready. Have flares, grab bag and

lifejackets on hand.

• Put position on chart and report to a shore station with a radio check.

• Have a meal and prepare simple food for later.

If heavy weather is expected to be encountered the vessel should be prepared.

First check the anchor gear to see if the anchor is snug in the hawse pipe or

securely positioned. If available, the stopper fitted, winch brake on, spurling

pipe and any other openings made watertight. Any heavy objects or cargo

that could be safely stowed below decks should be shifted. Deck cleared of

any loose ·debris or equipment or made secure. All watertight doors, hatch

covers and other openings to below deck secured and water tight. Freeing

ports and scuppers checked to see they are free and working and a deck life

line rigged. The bilge should be pumped, and any tanks, where possible,

either emptied or pressed up to reduce loss of stability through the "free

surface" effect. Check engine, steering gear, life saving and fire fighting

appliances. Put position on chart and report to a shore station with a radio

check.


•• -.Jo<• -

-1•., ••

... ....-

Sect on 1: Vessel Handling

If encountering heavy weather and rough seas is unavoidable, it should be

remembered that rough seas not only make the vessel uncomfortable, but

can also cause extreme structural damage, ofte11 the first and most convenient

action is to slow down the vessel's speed or change course, particularly if

the seas are on the stern or quarter. Taking a big sea head on, or a point or

two off the bow results is the safest way of handling the situation. Running

before heavy seas is dangerous because the hull is lifted by stem and you

can lose steerage and power often leading to a situation where the vessel is

"broached" or even capsized. Also when running before heavy seas there is

the possibility of the vessel being "pooped " or swamped by a following sea,

which can lead to broaching or capsizing.

WINO ANO SEA -----1..._

(i)

\

(i i)

BROACHING

WINO ANO SEA------

POOPING


-.....::


Boarding And Quartering Seas

When the sea is on the bow, the vessel rolls and pitches simultaneously, and

the resistance of the vessel's headway reduces the angle of roll. When the

vessel runs with the sea however, the roll increase because there is less

resistance forward, and because the wave runs past the vessel more slowly

and stays in contact longer. The result is a pronounced roll and pitch and the

possibility of heavy seas being taken over the stem. Because the sea is

traversing the vessel from astern, the rudder is less effective, and the vessel

may be slewed across the waves and broach. The added weight of water from

boarding seas can produce the danger of a capsize.

Turning In Heavy Weather

Do it before it is necessary, for example, before the vessel finds itself in

jeopardy off a lee shore. Tum in a smooth period when the waves are

momentarily flatter than the prevailing sea condition. Start the manoeuvre as

soon as the wave crest has passed the vessel (1). Reduce engine speed to allow

the sea to pass quickly. Tum the wheel hard over and tum the vessel in the

trough between the crests. Try to turn fast enough so you are head-to the next

wave. Apply power to complete the turn quickly but don't gather too much

headway (2). Reduce speed as soon as the vessel is nearly head to-weather

(3).

Don't turn when there is water on deck. Prudence dictates turning well before

damage or loss of stability dictates. A stem trawler with a ramp may have to

tum to weather before other vessel types because the sea will run up the ramp

and break on the deck. High bulwarks ordinarily make it comfortable to work,

but become a water trap in these conditions. Freeing ports must be kept clear.


- -- ·- - --


Heavy Weather Handling

Taking the seas on the port or starboard bow lessens some of the pitch (1). At

the right speed, going to weather is safer than having the weather abeam or

astern. If there is sufficient room. speed can be reduced until only steerageway

is maintained, and the vessel is "hove-Lo" or jogging with the seas at an angle

to the bow. When the conditions warrant, reduce speed and let the swells roll

by, or even use a drogue or sea anchor (2). Avoid the trough except in an

emergency. When you are moving broadside to the waves, turn the wheel

momentarily to take larger crests on the windward bow, then return to course

when conditions permit (3).

Sea Anchors

The sea anchor or drogue can be deployed in many situations, for example,

in deep water where the conventional anchor is impractical. It can be used

to slow the progression of the vess,eJ in a distress situation , or when a vessel

is being driven faster than the wave train in a following sea. When streamed

from the bow in heavy weather (heaved to) it will keep the bow into the

wind and waves, easing the stress on the vessel and creating a degree of

comfort for those on board.

In the situation of a sea anchor being needed, but one not being available,

suitable substitutes can be created using such material as: bundles of nets or

bags, or short lengths of wood, tied in such a way it can be deployed! to

retard the vessels progression.

The sea anchor when deployed from the vessel's bow or stern should have

enough scope so that the vessel and the sea anchor will not be on subsequent

wave crests at the same time.


-- 0

1) · --

2)


1.2.5 Interaction between Vessels

The pressure fields of two vessels in close proximity on the same or opposite

headings will interact and require corrective action to maintain course. The

large suction zone around the longer of the two vessels may be the

dominating factor in Interaction between vessels of significantly different

size. This may present a very dangerous situation for the smaller vessel,

particularly if it is overtaking.

Factors that increase the risk of interaction are, high speed, large size vessel,

narrow channel and shallow water. The pressure waves that create

Interaction are proportional to the square of the vessel speed, thus the effects

of all forms of interaction can be instantly reduced by reducing speed. Io

some cases consideration will have to be given to the loss of steering control

associated with speed reduction.

Overtaking vessels should avoid passing too close in open waters when there

is room to manoeuvre, and be particularly cautious in narrow channels when

overtaking or being overtaken.



1.2.6 Crossing a River Bar

A bar is an accumulation of sand or silt at the entrance of a river or a lake.

The build up could occur due to a current running across the mouth of the

river or entrance of the lake, depositing sand across it. Or also the

possibility that a river depositing silt at its mouth where it meets the sea.

This may be the result of a natural battle between the ocean trying to close the

opening and the flow from the inlet trying to keep it open, or the result of a

river depositing silt at its mouth.

Bars cause the waves to get steeper and in some cases break as they get

to the bar. For this reason it is important to take a number of precautions

and manoeuvre the vessel with extreme caution over a bar. Crossing bars

should be avoided if the wind and waves are in opposition as may occur

during strong land breezes or offshore winds, rough weather or ebb

(outgoing) tides.

If you intend to cross the bar for the first time ensure that you check with

the local authorities who would be able to give additional information

regarding the safest passage over the bar or the peculiarities of it and the

best crossing time.

When approaching the bar keep a good lookout for changes in the water

colour, the bluer the water, the deeper it is. Breakers or waves that are

steeper at one section of the wave front indicates shallow water.

If you intend to cross a bar, even one that you are familiar with, check

with the local authorities for the latest condition report and weather.

When crossing the bar the following factors need to be amongst those taken into

consideration:

• Advise Coast Guard or authorities of intentions

• Ensure all loose gear is stored and secured.

• Minimise the trim of the vessel

• Before approaching the bar test engines (both ahead or astern) and steering.

• While approaching the bar keep a close lookout for depth of water, smallest

waves, where the breakers are etc.

• Monitor the wave pattern waiting for a larger than normal set of waves.

• Increase power of the vessel to catch up with the bigger set of waves and

position the vessel above the crest of the wave (ensure the vessel does not

"surf" down the face of the wave).

If crossing against the incoming waves:

• Motor slowly to the breaking waves looking for the area where the waves

break last or even better, not at all. Wait for a flatter than usual stretch of

water and motor through.

• If there seems no respite in the waves slowly power through each

oncoming wave ensuring that you are not going to fast over each wave as

this would cause the vessel to "bottom out" if it pitches heavily.

• If possible make the crossing with the waves slightly on the bow so that the

vessel gently rolls over the crest of each wave.

Commercial Vessel Bar crossings. The following rules exist for commercial vessels

crossing coastal bars:

The Master must possess a bar endorsement on his Certificate of Competency

Day time crossing only

Wind strength below 20 knots

Wave height below 2 metres

Life Jackets to be worn by all on board

All persons in an open area of the vessel

1.3 Anchoring

After selecting of an appropriate anchoring position and ensuring that the

bitter end of the anchor rope/chain is secure the following procedure may be

adopted:

• Plan your approach to the position heading into the wind or the tidal

stream.

• Prepare the anchor for letting go by removing chocks or lashings. Test the

windlass and if necessary lower the anchor over the bow keeping it clear of

the water. This position is known as a-cock-bill. The anchor is now ready

to veer (under power) or disengage the clutch if the cable is to be surged.

• Check your echo sounder to reconfirm the depth, check your position.

• Stop engines.

If your vessel does not develop a slight sternway, give a short burst astern on

the engines.

Let go the anchor. Let the cable run out freely until it reaches the bottom.

Apply the brake slowly reducing the speed the cable is paid out so as to

ensure that it does. not "pile up" at the bottom.

When the final required length of cable has been deployed secure the brake.

Wat.ch the cable as the vessel is "brought up" or "has its cable". This is a

critical stage, because as the cable takes the weight of the vessel it is

important to observe the cable. If the anchor cable shudders or goes slack

and tightens again it indicates that the anchor has dragged om the bottom.

The cable should go taut and then slack again in a smooth fashion indicating

that the anchor has held.

Watch the cable for a couple of minutes to ensure that the anchor does not

drag. A small amount of stern power may be required to ensure that the

anchor has 'set'.


2')


Weighing Anchor

Before commencement of weighing anchor, ensure you have a capable

person forward. The vessel should be manoeuvred forward to take the weight

of the anchor and cable. When the cable/rope is "up and down" commence

heaving anchor. Have the deck hose ready to wash down the anchor if the

vessel is not fitted with an anchor wash. The person forward should watch

the anchor and cable come up to ensure it is not entangled. As soon as the

anchor is clear of the water and the person forward sees that the anchor is

clear, inform the wheel house and the vessel may then proceed.

Securing the Anchor for Sea

When the anchor is securely housed in the hawse pipe:

• Tighten the brake.

• Take the windlass out of gear.

• Put the "Riding Chock" or "Bower Stopper" in position.

• Secure the "Devils Claw" to the anchor chain.

• Position the metal guard plate over the spurting pipe.

• Seal the spurting pipe by cementing the plate in position.

Selecting an Anchorage

The following factors should be amongst those taken into consideration

when choosing a safe anchorage:

• Does the area provide shelter from the prevailing and expected winds

• It must be easily accessible

• Sufficient swinging room

• Sufficient depth of water at all levels of tide.

• Good holding ground if intending to anchor.

• Distance of the safe anchorage from your present position.

• Estimated Time to reach the anchorage in the prevailing conditions

• is it in the likely path of a storm

• effect of a storm surge in the anchorage

• any submarine cables or ordinance areas that make the haven unsafe.

Consult the chart of the area you are operating in and with your Master's

assistance determine a safe anchorage and an alternative.


,


FLUKE

SHANK

Parts of an Anchor

Types Of Anchors

Admiralty or Kedge

Until the DANFORTH and CQR.it was

considered to have the greatest holding

power. One disadvantage was that in

shallow water, vessel may sit on the fluke

C.Q.R Excellent holding power.

Hard to stow.

Stockless Has the advantage that it can be

heaved home in the hawse pipe.

Holding power less than the

Admiralty.

Danforth Good close stowing



Reef or Grapnel

Practical for use on reef. Not

suitable for general purpose

use.

Practical Activity

Understudy tile master of your vessel for a number of anchoring operations

and when you and the master are confident of your progress carry out the

operation under supervision of the master/facilitator. Keep a log of all the

checks carried out and the procedure followed.

The key competencies addressed by this activity are working with others as

a team, organising information and using technology.

Written Activity 3 Describe how you would anchor your vessel.


•


1.4 Berthing/Unberthing a vessel.

1.4.1 Briefing Cirew

Well before he vessel is to berth the crew should be made aware of the

following;

• Which side alongside.

• Positioning of fenders

• Number and position of ropes to be made ready

• Sequence of mooring ropes to be made fast.

• Check all unnecessary gear is secure

• Check all passengers seated

• Check all passengers notified to keep limbs inboard

Moori'ng Terms

Stem rope

Aft Breast

rope

Aft

Spring

For'd Spring

For'd Breast rope

Head

rope

The bow line runs through the fairlead or bow chock. The stem line runs

through the after fairlead or chock. These lines should be run well along the

wharf or berth and hold the vessel in.

Breast lines may be run perpendicular from the bow, midship or quarter to

keep the vessel from moving away from the wharf or berth.

Spring lines run from the bow and stem to stop ranging, (fore and after

movement of the vessel).

When securing alongside attention must be paid to the range of the tide, at

high tide leave enough slack to ensure the lines do not part as the tide falls.

Mooring lines should be checked at each turn of the tide. Use only lines

with eyes spliced onto tbe shore end so the line can be. tended on board.

Avoid sharp bends in the mooring lines where they pass through fairlead or

chocks, use some form of anti-chafing gear around the bends.


Section 1: VesselHandling

Securing the Line Inboard

There are many forms of fittings for this purpose, on large vessels the most

common are bitts, in smaller vessels we use cleats, stag born bollards or

sampson posts, in all cases first take two full turns of the line around the

base before the line is secured with figure eights.

Dipping the Eye

If two bights or eye splices are to be placed over the same bollard, the

second should lead up through the eye of the first so that either can be

removed independently.

Snubbing a Line on a Cleat or Bitts

Never try to hold a vessel without taking turns of the tine around the fitting.

Stand well back out of the bight of the line and at 90 degrees to the angle of

pull.

Spring Lines

Learn how to use the spring lines, bow or stem, for manoeuvring the vessel

in and out of tight spaces. They can be used to spring a vessel onto or off a

wharf or berth, to clear other vessel or when being warped around the end of

the berth.

Mooring lines should be checked frequently for signs of wear or fatigue.

When not in use lines should be correctly stowed and protected from the

weather and direct sunlight.

Unless there are very pressing reasons such as wind, tide, or berthing space, a

vessel should always be berthed taking advantage of transverse thrust_ That is

port side to for a vessel with a right handed propeller.

CORRECT

Learner's Guide - ABF 521: Nautical Knowledge Coxswain

37


Before berthing check astern and ahead controls for operation. Approach the

berth with sufficient speed to ensure positive steering, at an angle of around 20

to 30° with the bow heading for the far end of the berth. When the bow has

nearly reached the required position full starboard helm should be applied then

the forward way checked with a firm burst of astern power. This will swing

the stern in towards the berth, and bring the craft neatly alongside. See sketch

below.

Berthing Leaving the Berth

It is difficult, if not dangerous, to try to berth on the weather side of a jetty

or pontoon if the wind is strong. Under these conditions it is desirable to

seek a berth on the lee side.

Equally difficult is to come into a berth travelling in the same direction as a

strong tidal stream or current. If this is attempted the engine driving astern has

to take off the way of the vessel and provide speed astern through the water

equal to the tide or current. The craft should be turned to approach the berth

stemming the tide or current. If this is not possible mooring ropes may be

required to hold the bow to the berth as you turn the rudder away from the

berth and give the engine a short sharp burst ahead. This will cause the stern to

pushed towards the berth while the bow is kept in position by the mooring

rope.



Practical Activity

Understudy the master of your v,essel for a number of berthing

operations and when you and the master are confident of your progress carry

out the operation under supervision of the master/facilitator. Keep a log of all

the checks carried out, the procedure followed and crew briefing.

The key competencies addressed by this activity are working with others as a

team, organising information and using technology.

1.5 Securing to a buoy.

The advantages of mooring to a buoy over anchoring are:

• You do not need to worry about the anchor holding ground

• A much smaller swinging circle and.

• You can expect it to be more secure than any anchor.

A standard mooring buoy has a large eye at the top to which you may secure

your chain or wire as described below. However, many smaller moorings

have a securing warp permanently shackled to the buoy or mooring chain.

The procedure outlined below is to moor to a standard buoy, if yoU1 moor to

a smaller buoy, the approach to the buoy remains the same. The main

difference being you can reach the warp with a boat hook or similar device

and then drop it over the bits.

The first step in mooring to a standard buoy is to put a person onto the buoy,

this will normally mean putting the dinghy in the water or bring the vessel

alongside the buoy and put the person across.

You can now steam gently up to the buoy, stop with the bow alongside.

Make sure your approach is up-wind or into the tidal stream. While you hold

the vessel in position pass out a pick-up wire or rope, one end of which is

secured on the forward bitts. This pick-up rope is passed through the eye of

the buoy and back on board where it is secured.

This rope or wire will now hold you close to the buoy while you pass out and

secure the mooring chain or wire that will be shackled to the buoy.

Learner's Guide - ABF 521: Nautical Knowledge Coxswain

39


Don't forget to retrieve the person off the buoy.

The ship can now be allowed to fall back onto the main wire by slacking off the

pick-up rope. (The pick-up rope should be left in place if your stay is not of

long duration as you will use it in getting away from the buoy. Allow it to lie

completely slack).

Leaving A Buoy.

To leave the buoy the reverse of the mooring procedure must be adopted.

The vessel is about to proceed and is lying back on her cable or wire that is

shackled to the ring of the buoy.

Put a person on the buoy and if the pick up rope was removed, pass the pick

up rope or wire exactly as you did when tying up to the buoy.

Bring the ship close up to the buoy so that the weight is taken off the

mooring chain/wire. You can do this with main engines or by taking the

weight on the pick up wire/rope.

With weight now taken off the main mooring wire/chain it can easily be

unshackled by the person on the buoy.

Retrieve the person off the buoy.

Let go of the pick up rope.

As the vessel moves astern the pick up rope will be drawn through the eye of

the buoy and clear of it allowing the vessel to proceed out of the mooring.

Practical Activity

Understudy the master of your vessel for a number of mooring operations

and when you and the master are confident of your progress carry out the


checks carried out and the procedure followed.

The key competencies addressed.by this activity are working with others as

a team, organising information and using technology.


•


During the tow contact must be maintained either by radio or prearranged

signals and a visual watch should be kept on the tow. Remember the vessel

being towed is in charge. The appropriate lights and shapes required by the

collision regulations should be displayed.

It is possible to assist a vessel in calm water or confined conditions, by

simply coming alongside the other vessel and making fast with bow, stern

and spring lines. The two vessels must be positioned so that the propulsion

and steering gear of the assisting vessel are well aft of the other vessel and in

clear water, in this manner even larger vessels can be assisted and

manoeuvred. Using this method of towing in confined waters gives the

towing vessel better control over the tow.

If towing in heavy weather ensure that you use a long and heavy towing

cable which should sag in the water. This prevents the movement of either

vessel from jerking the towing cable reducing the chance of it parting.

Also:

• Ensure the towing cable is not chafing against a sharp structure.

• Grease the cable at the point of contact with the vessel.

• Ensure that the tow cable can be released in an emergency under all

conditions of load.

• If the towed vessel is manned use its steering gear.

To reduce yawing or sheering by the towed vessel:

• Stream a sea anchor behind the vessel being towed

• Rig a large sail or awning, either at the bow or the stern of the towed

vessel.

• Trim it by stern by transferring weights.

• Alter course and/or speed.

• Increasing speed tends to correct a yaw directly caused by list.

• Decreasing speed tends to correct a yaw produced by adverse trim.

• Set the towed vessel's rudder at an angle to counteract the sheer.

Practical Activity

Understudy the master of your vessel for a number of towing operations and

when you and the master are confident of your progress., carry out the


checks carried out and the procedure followed and the briefing of the crew

as required.

The key competencies addressed by this activity are working with others as a

team, organising information and using technology.



Practical Activities

Access a vessel in survey and practice the methods of berthing and

unberthing a vessel. using the transverse thrust of the vessel to benefit and to

disadvantage.

Berth and unberth the vessel using mooring ropes to assist the process.

Manoeuvre the vessel to determine the direction of rotation of the propeller.

Small Ships Manual. Chapter on Management of Vessels in Heavy Weather.

Australian Boating Manual. Chapter on boat Handling.

Feedbac.k

It is essential at this stage to carry out all practical activities on the vessel

with the express permission and supervision of your master or facilitator.

When carrying out the manoeuvre do not single mindedly think of

completing the manoeuvre but analyse the process and the associated factors

that must be considered while doing so.

Section Summary

We have looked at the theory behind vessel handling and also the practical

demonstration as to how these manoeuvres are carried out. It is essential to

have a thorough knowledge of the preceding section as the Coxswain 's job

is primarily that of safe vessel handling in conjunction with the various other

aspects.



Check your progress

Analyse "Squat" how does this phenomenon occur and what are its

effects?

Also consider how the effects of squat can be reduced.

2 What factors must be considered when choosing a safe anchorage?

3 Explain transverse thrust and the effect that it has on a left handed single screw vessel.


section 1: vessel handling - coxswain training information · manoeuvres to shorten in cable and...

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